1. Technical Field
The present invention relates to a laser light source device, an illumination device, an image display device, and a monitor.
2. Related Art
In recent years, in the field of opto-electronics including fiber-optic communication, light application measurement, light display, and the like, laser light source devices have been widely used.
As examples of laser light source devices, laser light source devices in which the wavelength of the fundamental wave laser is used directly without conversion, and laser light source devices in which a converted wavelength of the fundamental wave laser is used, are both well-known.
In the laser light source device in which the converted wavelength of the fundamental wave laser is used, a wavelength conversion element that converts the wavelength of the fundamental wave laser is well-known.
The wavelength conversion element is also called the Second Harmonic Generation element (SHG element).
In the laser light source device, the light emitted from the laser light source is resonated by using the laser light source device while combining an external resonator, the bandwidth of wavelength of the emitted light becomes narrow, thereby it is possible to obtain a high output of laser oscillation.
A laser light source device in which the external resonator structure is combined therein has been suggested, for example, in Japanese Unexamined Patent Application, First Publication No. 2001-284719.
In recent laser light source devices, improvement of illumination efficiency and additional miniaturization have been required.
However, in the laser light source device disclosed in the above-described Japanese Unexamined Patent Application, First Publication No. 2001-284719, not only the external resonator, but also complicated optical members such as a condenser lens, a concave lens and the like are necessary. Therefore, the constitution of the device becomes complex, and miniaturization of the device has not been realized.
Furthermore, in the case of attempting miniaturization of the device, deformations occur in the optical members, optical films disposed in an optical-path are broken, and the optical members are damaged, due to contact made with each optical member. Therefore, there is a problem in that the light utilization efficiency decreases due to the above-described deformation, breakage, and damage.
In order to solve the problem, it is possible that a surface of an optical member be connected with a surface of another optical member via an adhesive. However, the adhesive's quality can change due to the heat generated in the optical-paths. Therefore, there is a new problem in that it is difficult to efficiently utilize the light.